The revelation of God’s word is accompanied by tongues of fire in both Exodus and the Book of Acts, and the texts share crucial religious significance. Why? Because in both cases, God revealed his character to humanity, providing a standard by which even the worst sinner could be transformed for the better (via the Jerusalem Connection Report). 

Exodus also had implications for the priestly class, and how their leader (the high priest) communicated with God once a year in the Holy of Holies located at the Temple. How do we know this? According to the Jerusalem Connection Report, the first-century Jewish historian Josephus Flavius described how God spoke to the high priest via illuminated letters engraved on the priest’s breastplate. This symbology denoted the religious authority of the high priest as a figure capable of communicating directly with God.

Does anyone else mention the high priest and tongues of fire in first-century Palestine? Yes, the Essenes of Qumran copied and preserved the Dead Sea Scrolls and various other Jewish texts (via the Library of Congress). These include a scroll entitled “The Tongues of Fire.” According to the International Christian Embassy Jerusalem, the surviving parts of the scroll tell of “how tongues of fire would descend on the High Priest and speak through the Urim and Thurim and the stones on the breastplate of the High Priest.”

While the feast of Shavuot or Pentecost (aka Whitsunday) has long had religious significance for the Jewish people, it’s unclear when and how the earliest Christian churches observed the holiday (via Britannica). What happened during the New Testament event? According to Biblical Archaeology, Jews from across the diaspora gathered to hear the disciples speak. A melting pot of cultures, the audience members conversed in a diverse and rich variety of languages.

When the tongues of fire descended on the disciples, “each one heard them speaking in the native language of each [nation].” Biblical scholars still debate the nature of the miracle that occurred at Pentecost. Some claim the event involved two miracles, but others argued that only one miracle took place: the spontaneous ability to speak in another language.

Biblical Archaeology also explains that some scholars interpret what happened during Pentecost as the opposite of the events at the Tower of Babel in Genesis 11:1-9, when God confounded the nations by scrambling their languages. “While Pentecost doesn’t reverse the languages at Babel, it overcomes the problem for the sake of the salvation of the nations,” Ben Witherington III argues (via Biblical Archaeology). 

Christian references to the holiday suggest a 50-day observance period that began and ended with baptisms. Historically, some Christians also wore red vestments and even dressed the altar in red, symbolizing the “tongues of fire,” according to Britannica.

References to speaking in tongues also appear in material written by early theologians such as Tertullian, as reported by Evangelical Focus. Tertullian discussed the spiritual gift of interpreting these languages in 207. Others who mentioned this practice include Novatian in 360, Justin Martyr in 150, Eusebius in 339, Chrysostom in 407, and Augustine of Hippo in 430.

In the second century, Irenaeus referred to church members speaking in diverse languages “through the Spirit,” per Unsettled Christianity. These messages stood in stark contrast to a group of Christians who would develop the theological concept of Cessationism. What was Cessationism? The argument that the miracles of the New Testament, including healing and speaking in tongues, started and ended with the first generation of Jesus’ disciples. This controversy would have significant implications for church unity.

It also explains why later generations of “miracle-working” Christians would get derided and marginized by conservative Cessationists. There’s no faster way to get kicked out of many churches today than publicly praying “in the Spirit.” Interestingly, Irenaeus’s interpretation of the role of glossolalia to the faith couldn’t have been in greater opposition with many mainstream beliefs today. According to Unsettled Christianity, Irenaeus “seems to take the position that speaking in tongues is a sign of spiritual maturity, of spiritual perfection.”

The Moravians earned a reputation as one of the oldest Protestant denominations globally. But they also became known for speaking in tongues long before Pentecostals and Charismatics hit the scene, as reported by Moravians. The sect also set up a continuous prayer watch that ran uninterrupted 24 hours a day for 100 years.

A group of 17th-century French prophets known as the Camisards spoke in incomprehensible languages, according to Michael Pollock Hamilton’s “The Charismatic Movement.” They would sometimes also interpret the tongues they spoke, and they differed from the Cessationists when it came to the role of miracles in today’s world. They claimed, “God has no where in the Scriptures concluded himself from dispensing again the extraordinary Gifts of His Spirit unto Men.” Despite their radical beliefs, the French prophets took social respectability to the next level, maintaining well-kept appearances, per “The French Prophets: A Cultural History of Religious Enthusiasm in PostToleration England (1689-1730).” In other words, they represented a far cry from stereotypes about backwoods tongues speakers.

Early Quakers also participated in glossolalia, according to PCPJ. You’ll never look at the Quaker Oatmeal guy quite the same! While the thought of sober Quakers getting caught up in ecstatic speech might appear counterintuitive at first glance, think again. As it turns out, the Quakers have long-held linkages with the Charismatic Movement.

In the 20th century, Pentecostalism and a later Charismatic Movement brought glossolalia back to the forefront. What proved the pivotal event in these movements? According to the Apostolic Archives, the Azusa Street Revival, a Pentecostal revival led by African American preacher William J. Seymour, contributed to a significant movement in southern California.

Eyewitnesses described the Azusa Street Revival as a frenetic admixture of miracles, glossolalia, “dramatic worship services,” and indiscriminate fellowship between people of every class, color, and background. The movement endured heavy criticism, particularly from bewildered members of the media. Nonetheless, it is considered to be the “primary catalyst” of a Pentecostal resurgence in the 20th century (via Assemblies of God).

In 2006, researchers at the University of Pennsylvania studied images of peoples’ brains while they spoke in tongues, and they came to some fascinating conclusions (via the New York Times). Contrary to centuries of stigma, individuals who speak in tongues rarely have mental illness, and they often prove more emotionally stable than those who don’t. Their conclusion? The act of glossolalia involves submission to a higher power leading to a “very intense experience of how the self relates to God,” per Science. Moving forward, it’ll be fascinating to see what science has to say about this ancient practice.